Prepare the Dry Base: In a very large mixing bowl, combine the 1 1/2 cups of old-fashioned rolled oats, the 1/2 cup of protein powder, the 1/4 cup of ground flaxseed or chia seeds, and the 1/2 teaspoon of salt. Use a whisk or a large wooden spoon to stir these dry ingredients together thoroughly until they are uniformly mixed.

Add the Wet Ingredients: Pour the 1 cup of creamy peanut butter, the 1/2 cup of liquid sweetener (honey or maple syrup), and the 1 teaspoon of pure vanilla extract directly into the dry mixture bowl.

Combine and Mix: Begin mixing the ingredients using a strong wooden spoon or a rubber spatula. Continue to fold and press the mixture until all the dry ingredients are moistened by the peanut butter and sweetener. This step requires a good amount of pressure.

Incorporate Coconut and Test Consistency: Add the 1/2 cup of shredded coconut into the bowl. Mix again until the coconut is evenly distributed throughout the dough. The mixture should be firm, sticky, and hold together easily when pressed between your fingers. If the mixture seems crumbly or too dry to hold a shape, add 1 to 2 tablespoons of milk at a time until the desired consistency is reached.

Chill the Dough (Optional but Recommended): Cover the mixing bowl tightly with plastic wrap and place it into the refrigerator to chill for 30 minutes. Chilling the mixture makes the rolling process much cleaner and helps the balls maintain their shape.

Prepare Rolling Station: While the dough is chilling, pour the extra 1/4 cup of shredded coconut onto a shallow plate or a small baking sheet. Line a separate baking sheet with parchment paper.

Form the Protein Balls: Remove the dough from the refrigerator. Use a small cookie scoop (about 1 to 1.5 tablespoons capacity) or measure out portions with a regular tablespoon. Roll each portion firmly between the palms of your hands to form a smooth, tight sphere.

Coat the Balls: Immediately roll the formed balls in the plate of extra shredded coconut, pressing lightly to ensure the coconut adheres fully to the surface of the ball. Place the finished coconut-coated balls onto the parchment-lined baking sheet.

Final Set and Storage: Once all the mixture is rolled, place the sheet back into the refrigerator for another 15 minutes to allow them to fully set before serving. Store the protein balls in an airtight container in the refrigerator for up to 7 to 10 days, or freeze them for up to 3 months.